The invention relates to articles formed of synthetic material, but replicating a natural material, and in particular to piano key covers formed of synthetic ivory substitute material.
It has been the practice, for centuries, to manufacture piano key covers from natural ivory. In more recent years, initially due to concerns of cost and more recently due to concerns of wildlife conservation, it has been proposed to substitute synthetic plastic materials which have the appearance of natural ivory, see, e.g., Ishida U.S. Pat. No. 4,840,104 and Vagia U.S. Pat. No. 4,346,639. However, it has been found by experienced pianists that the feel of piano key covers of natural ivory differs significantly from that of key covers formed of synthetic material, and that the quality of their performance on pianos having key covers of synthetic material is perceptibly diminished.